US2727365A

US2727365A - rosell

Info

Publication number: US2727365A
Authority: US
Publication date: 1955-12-20
Anticipated expiration: 1972-12-20

Description

Dec. 20, 1955 ROSE-LL 2,727,365

AIR CONDITIONING SYSTEM FOR SUBTERRANEAN WORKSHOPS Filed April 15, 1952 2 Sheets-Sheet 1 Fig.1

Dec. 20, 1955 AIR CONDITIONING SYSTEM FOR Filed April 15, 1952 A. F. ROSELL SUBTERRANEAN WORKSHOPS 2 Sheets-Sheet 2 United States Patent AIR CONDITIONING SYSTEM FOR SUBTERRANEAN WORKSHOPS Axel Fl'dl'ik Regen, Djursholm, near Stockholm, Sweden Application April 15, 1952, Serial No. 282,506

Claims priority, application Sweden April 23, 1951 9 Claims. (Cl. 62129) In subterranean workshops the heat developed per unit of floor surface by machinery and lamps is, as a rule, very high. Practically all the developed heat must be removed by mechanical means, if the temperature in the locality is to be kept at a reasonable level. In the beginning the heat flow to the surrounding rock is considerable, but it rapidly decreases and very soon reaches so low a value that its influence on the heat balance is negligible. Simultaneously, the surface temperature of the walls approaches that of the room.

Up to the present, similar localities have been cooled exclusively by means of air conditioning. Cool air from the outside or from cooling coils is supplied to the locality, where it is heated by the machinery, the lamps and the occupants, cooling in that way the room and assuming its temperature. The heat effect that the supplied air can remove is proportional to the product of the air quantity and the difiFerence between room temperature and supply air temperature. In practice it has proved difiicult to supply air cooler than about 8 below the temperature of the room without disturbing air drafts. This settles the minimum air quantity to be used. But disturbing drafts may also arise on account of great air quantities only, irrespective of the air temperature, and when the quantity of heat dissipated per unit of floor space exceeds a certain limit, it is therefore practically impossible to avoid such disturbances. This is the reason why it has proved difficult to keep a lower temperature than about 21 C. in subterranean workshops and the like without complaints, so high a room temperature being necessary to compensate for the excessive air motion in some parts of the workshop. The relative humidity has then seldom been below 60% but as a rule higher, the surface temperature of the room about the same as that of the room. For active work, this temperature is too high for comfort, which requires a resulting temperature, as defined by F. A. Missenard not higher than about 16 C. (Etude physiologique et technique de la ventilation). The high resulting temperature which, up to the present it has not been possible to avoid in localities of this kind, causes a senation of tiredness and discomfort among the occupants.

According to the invention, the draft problems at the suitable resulting temperature are eliminated by reducing the air quantities and removing a great part of the developed heat otherwise than by the supplied air, namely by radiation and convection to the ceiling, the floor and the walls, which are cooled, preferably by means of cooling coils, encased in the material. A cooling medium of suitable quality and temperature is kept streaming through the coils.

Due to the fact that the heat transmission between the cooling coils and the surrounding building material is much more favorable than that which can be attained between cooling coils and air, it is possible with a system according to the invention to raise the temperature level of the cooling process.

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Thanks to this higher temperature level the efficiency of the cooling machinery is improved, and further the heat pump principle can be applied with very good economy, the heat from the condenser of the cooling machinery being used for heating the supplied fresh air in cold weather.

The principle of the invention is explained in the following description which only refers to one type of installation, chosen as an example within the range or" the invention. This example is illustrated on the attached drawings, on which corresponding parts are marked with corresponding figures throughout.

Fig. 1 shows schematically a cross section of a subterranean workshop with devices for cooling by means of air conditioning only, according to systems used until now.

Fig. 2 shows a workshop, similar to the one shown in Fig. 1 with a cooling installation designed as per the invention.

Fig. 3 shows a principle diagram for the cooling, heating and air conditioning, which can be applied on a plant as per Fig. 2.

Fig. 4 and Fig. 5 show some details of encased cooling coils.

On the drawings the different parts are marked with slanting figures and the temperatures in centigrades with upright ones. The flowing media are marked with arrows and a little letter which explains the kind of medium according to the following code:

a supplied air (inlet air) b outlet air (also marked with a zigzag stroke over the arrow) 0 hot water for heating and condenser cooling d cooled water for air cooling e cooled water for cooling of the ceiling, walls and/or floor 1 cold water for condenser cooling g compressed cooling medium, for instance compressed ammonia vapor h condensed cooling medium i evaporated cooling medium The principal apparatus are represented with upright capitals followed by numbers.

According to Fig. 1 the locality is formed by a space 1 in a rock or under the ground 2. This space is panelled by means of a self sustaining ceiling arch 3, walls 4, and a inner floor 5.

Between the ceiling 3 and the surface 6 or" the rock there is a space 7 which can beused for air ducts and pipings. The duct 8 supplies cooled and dehumidified air a of about 12 into the room 1 through an air distributor, and the used air b leaves the room through the ducts 9.

The plant as per Fig. 2 differs from that as per Fig. 1 by a cooling coil 10 encased in the arch 3. The temperatures marked on the drawings are of course only examples and averages. In reality variations occur, locally and temporarily, depending upon the place of the heat sources, the heat dissipation and other variable factors. The essential diiierence between Fig. l and Fig. 2 with respect to the temperature is that, according to Fig. 2, the ceiling has a lower temperature than the air in the locality and also lower than the temperature of the walls and the floor, which, thanks to their radiation to the ceiling, will be cooler than the air of the room. Since a normally dressed adult, Working moderately, dissipates most of his heat by radiation, the lowering of the result temperature, being directly cooled by encased cooling 3 coils. From a physiological point of view, this kind of heat dissipation from the human body is more favorable than that obtained for instance in a room heated by a warmceiling. "I I Another considerable advantage is that {the temperature in the space .7 will the lower when the room is cooled as per Fig. 2. In the example chosen, this temperature will thus be about 11 instead of 20- lnsulation'of the ducts 8 and of the pipings for cold water is therefore not-necessary, and no risk for condensation is at hand, A characteristic of the invention is that the temperature in the cooling coils is .not essentially lower than the dew point of the air in .the room. At 20 and 50% relative humiditythe dewpoint is about 9. Fig. 3, shows the technical arrangement of an installation asper Fig. 2. The air is treated (cooled, dehumidified, heated, etc.) in an air conditioning unit 11, which is connected to the outside by a vertical duct The outlet duct 9 ends in the unit 11. The air quantities are controlled by dampers 13 and-14. The outletair is exhausted by a fan 17 through a'damper 15, a duct 16 to a discharge opening 18. Of course, part of the air leaves through doors, etc.

The unit 11 contains a cooling 'coil 19 a heating coil 20 and a fan v2.1, the discharge opening of which is connected to the duct 8.

The cooling coil 10 is connected to a cold water generator E1 by means of

pipings

22 and 24, and the water is circulated by a pump 23. The heating coil 20 is connected to a condenser C1 by means of pipings 28 and .29, and the circulationis obtained by a pump 30. For emergency a hot water heater W, for instance an electric one, is inserted in the piping 28. The cooling coil 19 is connected to a cold water generator E2 by means of

pipings

25 and 26 and the circulation is obtained'by apump 27.

The cooling system is divided into-two circuits, each one with its compressor, CR1 and CR2, respectively.

The compressed ammonia vapor (Freon or another refrigerant) g leaving the compressor CR1 through the piping 31 is branching through two

pipings

32 and 33 to one condenser C1 and another one C2. In the condensers the ammonia vapor encounters cooling coils 48 and 49 respectively whereby it is condensed to liquid and continues by the pipings 34 and 35 respectively to a generator or heat exchanger E1, in which it is passing two coils 51 and 52 respectively, and is evaporated as known, thereby cooling the surrounding water.

In the condenser C1 thepassing cooling water is heated fromentering at about 30 to about 40" The condenser C2, which is a stand-by condenser, is cooled by water f from the piping .39, which passes through the pump 40 and leaves by the piping 41. This cooling water 1 may be lake-water or water from a cooling tower, etc.

The corresponding parts for the compressor CR2 would not need any further explanation since they are well known to the specialist. I

The compressor CR2 with a condenser C3 and agenerator E2 belongs to the plant for air cooling. The air leaving the coil 19 may have a temperature as low as about 12, and in order to avoid too large cooling surface to be required for the cooling coils 19, the circulating cooling medium d must have a relatively low temperature, in the example shown on the drawing --2.

For the coil 10, on the other hand, cooling water of about +l0 can be used. This means that the cooling machinery can work at a higher temperature level, that is, with better economy, and ordinary water, instead of brine, can be used for feeding the coils. Thanks to the,

comparativelyhigh temperature level of the cooling process, the cooling water from the condenser C1 can be used for feeding the heating coil 20, according to the principle of the heat pump.

It is of course also possible to use for instance lake water forfeeding coil '10, if such water of suitable temperature is available. 'This,however, would require stainless tubes to be used for the coil. Another method'that can be used during part of the year is to cool the water for coil by means of a heat exchanger, fed with lake water or similar.

When cooling with air conditioning only as per Fig. l, the cooling circuits belonging to the compressor CR1, in the diagram, Fig. 3, are omitted. In this case the whole cooling process must be carried through at the lower temperature level, which, beside the inconveniences from a technical point of view, also means an essentially higher power consumption. Theoretically, it is possible to apply the heat pump principle, but in practice it is hardly possible due to the bad efiiciency.

Many difierent embodiments and combinations are possible within the scope of the invention. Some of them are already mentioned above. Instead of or together with the cooling of the arch 3 of the ceiling, the walls 4 may be cooled entirely or partly. The floor may also be cooled, but in general it is not to be recommended. The temperatures are not bound to those given in the example but must be selected depending upon the kind of activity. Consequently both lower and higher temperatures than those in the example are possible and of course the relations between the different temperatures need not be the same as in the example.

The-Figures 4 and 5 show an embodiment of part of a cooling coil. The tubes 10 run in parallel between larger supply and return pipes. The arch 3 as a rule consists of reinforced concrete. It is therefore suitable to use iron or steel tubes for the cooling coils 10.

Theoretically it would be possible to connect the coils 1-0 to the cooling machine and cool them by direct expansion. In practice, however, this is generally not to be recommended.

it is not necessary that the ceiling 3, the walls 4 and the floor 5 are free from the rock or the ground. They may be joined entirely or partly with the rock or there may be only a small space in between.

The invention is not limited to subterranean workshops and the like, even if it is especially suitable for that kind of localities. It may be applied in over ground localities also, especially where these are surrounded by other heated premises.

The cooling coils 10 can be put in the walls and the floor entirely or partly, and it is possible to use different temperatures of the cooling medium e so that different temperaturesvcan be obtained onthe various partso'f the surfaces, for instance in order to compensate local variations in the heat radiation.

I claim 1. A cooling and air conditioning arrangement for a room located in a subterranean cavity comprising a casing forming the ceiling, walls and vfloor of said room spaced from the adjacent walls of said cavity, means for supplying conditioned air to said room and means'for radiant cooling of said room and the space between said casing and said cavity, said radiant cooling means com prising cooling coils embedded in said casing.

2. A cooling and air conditioning arrangement for a room located in a subterranean cavity comprising a casing forming the ceiling,walls and floor of said room spaced from the adjacent walls of said cavity, means for supplying conditioned ,air to said room and means for radiant cooling .of said room and the space between said casing and said cavity, said radiant cooling means comprising cooling coils embedded in the ceiling of said .3. A cooling and air conditioning arrangement for a room located in a subterranean cavity comprising a casing forming the ceiling, walls and floor of said room spaced from the adjacent walls of said cavity, means for supplying conditionedair to said room and means for radiant cooling of said room and the space between said casing and said cavity, said radiant cooling means comprising cooling coils embedded in said casing and said means for supplying conditioned air to said room including a heater, a condenser and an evaporator, said heater being fed by a heating medium serving as a cooling medium for said condenser and said evaporator being heated by a medium circulating through said cooling coils and said evaporator.

4. A cooling and air conditioning arrangement for a room located in a subterranean cavity comprising a casing forming the ceiling, walls and floor of said room spaced from the adjacent walls of said cavity, means for supplying conditioned air to said room and means for radiant cooling of said room and the space between said casing and said cavity, said radiant cooling means comprising cooling coils embedded in said casing and means for maintaining the surface temperature of said cooling coils above the dew point of the air in said room.

5. A cooling and air conditioning arrangement for a room located in a subterranean cavity comprising a casing forming the ceiling, walls and floor of said room spaced from the adjacent walls of said cavity, means for supplying conditioned air to said room and means for radiant cooling of said room and the space between said casing and said cavity, said radiant cooling means comprising cooling coils embodded in said casing, said means for supplyng conditioned air to said room including a heater, a condenser and an evaporator, said heater being fed by a heating medium serving as a cooling medium for said condenser and said evaporator being heated by a medium circulating through said cooling coils and said evaporator and means for maintaining the temperature of the medium circulating through said cooling coils at a temperature that corresponds to a surface temperature on said cooling coils approximately that of the dew point of the air in said room.

6. A cooling and air conditioning arrangement for a room located in a subterranean cavity comprising a casing forming the ceiling, walls and floor of said room spaced from the adjacent walls of said cavity, means for supplying conditioned air to said room and means for radiant cooling of said room and the space between said casing and said cavity, said radiant cooling means comprising cooling coils embedded in said casing, said means for supplying conditioned air to said room including a heater, a condenser and an evaporator, said heater being fed by a heating medium serving as a cooling medium for said condenser and said evaporator being heated by a medium circulating through said cooling coils and said evaporator and means for maintaining the temperature of the medium circulating through said cooling coils at a temperature that corresponds to a surface temperature on said cooling coils higher than that of the dew point of the air in said room.

7. A cooling and air conditioning arrangement for a room located in a subterranean cavity comprising a easing forming the ceiling, walls and floor of said room spaced from the adjacent walls of said cavity, means for supplying conditioned air to said room and means for radiant cooling of said room and the space between said casing and said cavity, said radiant cooling means comprising cooling coils embedded in said casing, said means for supplying conditioned air including ducts located in the space between said casing and the walls of said cavity.

8. A cooling and air conditioning arrangement for a room located in a subterranean cavity comprising a casing forming the ceiling, walls and floor of said room spaced from the adjacent walls of said cavity, means for supplying conditioned air to said room and means for radiant cooling of said room and the space between said casing and said cavity, said radiant cooling means comprising cooling coils embedded in said casing, said means for supplying conditioned air including ducts located in the space between said casing and the walls of said cavity and said cooling coils being connected to conduits also located in the space between said casing and the walls of said cavity.

9. A cooling and air conditioning arrangement for a room located in a subterranean cavity comprising a casing forming the ceiling, walls and floor of said room spaced from the adjacent walls of said cavity, means for supplying conditioned air to said room and means for radiant cooling of said room and the space between said casing and said cavity, said radiant cooling means comprising cooling coils embedded in said casing, said means for supplying conditioned air including uninsulated ducts located in the space between said casing and the Walls of said cavity and said cooling coils being connected to conduits also located in the space between said casing and the walls of said cavity.

References Cited in the file of this patent UNITED STATES PATENTS 2,392,240 Frankel Ian. 1, 1946 2,463,881 Kemler Mar. 8, 1949 2,489,130 Harter Nov. 22, 1949 FOREIGN PATENTS 241,604 Switzerland Aug. 16, 1946 605,578 Great Britain July 27, 1948 614,627 Great Britain Dec. 20, 1948 817,136 France Aug. 26, 1937